Locking any layer in Illustrator (or Photoshop, or InDesign) has no effect in PDFs.
Layer locking is a function of the originating application and has no bearing on output.
You're free to try this yourself. You should be able to open your PDF and edit the text in Acrobat. But then, you'll also be able to use the Object Touch Up Tool to edit anything else as well.
It's difficult to limit editing but allow some. Generally, it's best to either supply a file to be edited, or supply a file which is not to be edited. But with Illustrator it's pretty impossible to supply an uneditable file. You can make editing some things much more difficult, but you can't prevent editing overall in a vector file, even as a PDF.